Drive mechanism and method

ABSTRACT

A drive train is used at least including an input shaft and an output shaft. A clutch member is rotatable by a clutch shaft about an axis of rotation. The clutch shaft is supported for lateral movement along the axis of rotation to move the clutch member to cooperate with the drive train at a first lateral position to cause the output shaft to turn and to move the clutch member to a second lateral position to disengage the output shaft from rotation of the input shaft. A permanent magnet is supported by one end of the clutch shaft and arranged for receiving an external magnetic biasing force along the axis of rotation to selectively move the clutch member between the first and second lateral positions. A traveling shaft can be used to support a selected gear for movement by the permanent magnet to implement transmission and reversing configurations.

RELATED APPLICATIONS

This application is a continuation application of copending U.S. patentapplication Ser. No. 13/761,980 filed on Feb. 7, 2013, which is adivisional of U.S. patent application Ser. No. 13/441,504 filed on Apr.6, 2012 and issued as U.S. Pat. No. 8,393,454 on Mar. 12, 2013, which isa continuation of U.S. patent application Ser. No. 13/094,241 filed onApr. 26, 2011 and issued as U.S. Pat. No. 8,172,057 on May 8, 2012;which is a continuation of U.S. patent application Ser. No. 11/939,693filed on Nov. 14, 2007 and issued as U.S. Pat. No. 7,954,614 on Jun. 7,2011, the disclosures of which are incorporated herein by reference.

BACKGROUND OF THE INVENTION

The present invention is related generally to the field of a drivemechanism for use in a drive train and, more particularly, to amagnetically actuated drive mechanism.

Drive and clutch arrangements are utilized in a diverse array ofapplications, for example, whenever it is desired to break a driveengagement between a driving member and a driven member. Many clutcharrangements operate in a way which biases the overall clutch mechanismto an engaged configuration in an absence of external actuation. Otherarrangements operate by biasing the overall mechanism to a disengagedconfiguration. One example of the latter is seen in U.S. Pat. No.5,609,232 (hereinafter the '232 patent) which uses permanent magnets tobias the mechanism to a disengaged position. The engaged configurationis achieved by using electromagnets to overcome the force that isapplied by the permanent magnets. Unfortunately, it is considered thatthere are at least two concerns that are associated with the type ofmechanism that is taught by the '232 patent, and which are shared to asignificant extent with the prior art, in general. First, maintainingthe engaged configuration requires a continuous current flow in theelectromagnet assemblies. Of course, this concern is likely to be sharedwith any prior art that uses an electromagnet. Thus, there is acontinuous power consumption, which may be of concern in applicationsthat rely on a limited source of electrical power such as, for example,battery power. Second, a loss of power in the engaged configurationresults in movement from the engaged configuration to the disengagedconfiguration. Accordingly, the use of the mechanism of the '232 patentmay be problematic when there is a need to avoid power failure relatedchanges in the operational status of the clutch mechanism. In theinstance of the use of electromagnets, it should be appreciated that afailure of the electromagnets can mimic a power failure related change,likewise resulting in a change in the operational status of the clutchmechanism.

The foregoing examples of the related art and limitations relatedtherewith are intended to be illustrative and not exclusive. Otherlimitations of the related art will become apparent to those of skill inthe art upon a reading of the specification and a study of the drawings.

SUMMARY

The following embodiments and aspects thereof are described andillustrated in conjunction with systems, tools and methods which aremeant to be exemplary and illustrative, not limiting in scope. Invarious embodiments, one or more of the above-described problems havebeen reduced or eliminated, while other embodiments are directed toother improvements.

In general, a drive train is used at least including an input shaft andan output shaft. In one example, a clutch arrangement includes a clutchmember that is configured to rotate about an axis of rotation. A clutchshaft supports the clutch member for rotation about the axis of rotationand includes a pair of opposing ends. The clutch shaft is furthersupported for lateral movement along the axis of rotation such that theclutch member cooperates with the drive train at a first lateralposition in a first operational mode to cause the output shaft to turnresponsive to rotation of the input shaft and the clutch memberdisengages the drive train at a second lateral position in a secondoperational mode to disengage the output shaft from rotation of theinput shaft. A clutch-drive permanent magnet is supported by one of theopposing ends of the clutch shaft for rotation in unison with the clutchshaft and arranged for applying a magnetic biasing force along the axisof rotation to move the clutch member between the first lateral positionand the second lateral position. A field generating arrangement producesa first magnetic field configuration that causes the clutch-drivepermanent magnet to move the clutch shaft and, thereby, the clutchmember away from the second lateral position to bias the clutch memberinto the first lateral position, and for producing a second magneticfield configuration that causes the clutch-drive permanent magnet tomove the clutch member away from the first lateral position to bias theclutch member into the second lateral position.

In another example, a clutch member is configured to rotate about anaxis of rotation. A clutch shaft supports the clutch member for rotationabout the axis of rotation and includes a pair of opposing ends. Theclutch shaft is further supported for lateral movement along the axis ofrotation such that the clutch member cooperates with the drive train ata first lateral position in a first operational mode to cause the outputshaft to turn responsive to rotation of the input shaft and disengagesfrom the drive train at a second lateral position in a secondoperational mode to disengage the output shaft from rotation of theinput shaft. A permanent magnet is supported by one of the opposing endsof the clutch shaft and arranged for receiving an external magneticbiasing force along the axis of rotation to selectively move the clutchmember between the first lateral position and the second lateralposition.

As another example, a drive train at least includes an input shaft andan output shaft. A gear arrangement is configured to rotate about anaxis of rotation. A traveling shaft supports the gear arrangement forrotation about the axis of rotation. The traveling shaft includes a pairof opposing ends and is further supported for lateral movement along theaxis of rotation such that the gear arrangement serves as a travelinggear arrangement that cooperates with the drive train at a first lateralposition in a first operational mode to cause the output shaft torespond in a first way responsive to rotation of the input shaft and tocooperate with the drive train at a second lateral position in a secondoperational mode to cause the output shaft to respond in a second wayresponsive to rotation of the input shaft. A permanent magnet issupported by one of the opposing ends of the traveling shaft for movingwith the traveling shaft and arranged for applying a magnetic biasingforce along the axis of rotation to move the traveling gear arrangementbetween the first lateral position and the second lateral position. Afield generating arrangement produces a first magnetic fieldconfiguration that causes the permanent magnet to move the travelingshaft and, thereby, the traveling gear arrangement away from the secondlateral position to bias the traveling gear arrangement into the firstoperational mode with the traveling gear arrangement moved to the firstlateral position, and for producing a second magnetic fieldconfiguration that causes said permanent magnet to move the travelinggear arrangement away from the first lateral position to bias thetraveling gear arrangement into the second operational mode with thetraveling gear arrangement moved to the second lateral position.

In addition to the exemplary aspects and embodiments described above,further aspects and embodiments will become apparent by reference to thedrawings and by study of the following descriptions.

BRIEF DESCRIPTION OF THE DRAWINGS

Exemplary embodiments are illustrated in referenced figures of thedrawings. It is intended that the embodiments and figures disclosedherein are to be illustrative rather than limiting.

FIG. 1 is a diagrammatic illustration, in elevation, of a drive trainand clutch arrangement with the clutch arrangement in an engagedposition.

FIG. 2 is a diagrammatic illustration, in elevation, of the drive trainand clutch arrangement of FIG. 1 with the clutch arrangement in adisengaged position.

FIG. 3 a is a diagrammatic view, in elevation, of one embodiment of anactuator mechanism that is suitable for use with the clutch arrangementof FIGS. 1 and 2.

FIG. 3 b is a diagrammatic view, in perspective, of the actuatormechanism of FIG. 3 a, shown here to illustrate further details of itsstructure.

FIG. 4 a is a diagrammatic side view, in perspective, of anotherembodiment of an actuator mechanism that is suitable for use with theclutch arrangement of FIGS. 1 and 2.

FIG. 4 b is a diagrammatic bottom view, in perspective, of the actuatormechanism of FIG. 4 a, shown here to illustrate further details of itsstructure.

FIG. 5 is a schematic diagram showing one embodiment of an electricaldrive arrangement that is suitable for use with the actuator mechanismsof FIGS. 3 a and 4 a, and further illustrates a status monitoringarrangement.

FIG. 6 is a is a diagrammatic illustration, in elevation, of a modifieddrive train and clutch arrangement with the clutch arrangement in anengaged position and including one embodiment of an electromagneticactuator mechanism.

FIGS. 7 and 8 are diagrammatic views, in elevation, of one embodiment ofa drive train including a gear shift configuration that is producedaccording to the present disclosure, where FIG. 7 illustrates a firstoperational mode and FIG. 8 illustrates a second operational mode.

FIGS. 9 and 10 are diagrammatic views, in elevation, of one embodimentof a drive train including a reversing gear shift configuration that isproduced according to the present disclosure, where FIG. 9 illustrates aforward operational mode and FIG. 10 illustrates a reverse operationalmode.

FIGS. 11 and 12 are diagrammatic views, in elevation, of one embodimentof a drive train including a clutch arrangement that is producedaccording to the present disclosure.

DETAILED DESCRIPTION

The following description is presented to enable one of ordinary skillin the art to make and use the invention and is provided in the contextof a patent application and its requirements. Various modifications tothe described embodiments will be readily apparent to those skilled inthe art and the generic principles taught herein may be applied to otherembodiments. Thus, the present invention is not intended to be limitedto the embodiments shown, but is to be accorded the widest scopeconsistent with the principles and features described herein includingmodifications and equivalents, as defined within the scope of theappended claims. It is noted that the drawings are not to scale and arediagrammatic in nature in a way that is thought to best illustratefeatures of interest. Descriptive terminology such as, for example,upper/lower, right/left, front/rear top/bottom, underside and the likemay be adopted for purposes of enhancing the reader's understanding,with respect to the various views provided in the figures, and is in noway intended as being limiting.

Turning now to the figures, wherein like components are designated bylike reference numbers whenever practical, attention is immediatelydirected to FIG. 1 which diagrammatically illustrates one embodiment ofa clutch arrangement, generally indicated by the reference number 10 andforming part of a drive train 20. In the present example, the clutcharrangement is illustrated in an engaged position. The drive train isdriven, for example, by a motor 22 which drives a first gear set 30. Themotor may be any suitable type such as, for example, electric, internalcombustion and pneumatic. A first gear 32 of the first gear set isdriven by a shaft gear 34 of motor 22. A second gear 36 of the firstgear set is supported on a first gear set shaft 38, along with firstgear 32, for co-rotation with the first gear. Bearings 40 are used tosupport first gear shaft 38. It should be appreciated that any suitableform of bearing may be used, dependent upon a particular application andin view of this overall disclosure, such that first gear shaft 38 isallowed to rotate freely, while retained along its axis of rotation.Motor 22 rotates shaft gear 34 in an exemplary direction 50, that isindicated by an arrow, to rotate first gear set 30 in an opposingdirection 52, indicated by an arrow. Motor shaft gear 34 and first gear32 may be of any suitable type including, for example, toothed gearssuch as spur gears and gears having projecting “dog” type teeth. Teethhave not been illustrated on the gears in the figures, since there arealternative configurations in each instance. Further, in someembodiments, such as is the case with motor shaft gear 34 and first gear32, these gears may be replaced by pulleys which support a suitableflexible belt. In still other embodiments, shaft gear 34 and first gear32 may be eliminated and the drive shaft of motor 22 may be directlycoupled to first gear set shaft 38, as will be further described.

Still referring to FIG. 1, a second gear set 60 can be essentiallyidentical in construction to first gear set 30 having its componentsindicated by like reference numbers with an appended prime (′) mark thathas been provided for descriptive clarity. In the present example, firstgears 32 and 32′ are at least generally aligned in order to engageclutch arrangement 10. The latter includes a first clutch gear 70 and asecond clutch gear 72 fixedly supported on a clutch shaft 74. The clutchshaft is, in turn, rotatably supported by bearings 76 along an axis ofrotation of the clutch shaft. Any suitable type of bearing may be usedas bearings 76, so long as clutch shaft 74 is able to rotate about itsaxis of rotation as well as being supported for bi-directional lateralmovement through a range of positions along the axis of rotation, asindicated by a double-headed arrow 80. For purposes of providingselective lateral movement and biasing of clutch shaft 74, a permanentmagnet 90 is supported, for example, by or near one free end of theclutch shaft. Magnet 90 may be attached to the clutch shaft in anysuitable manner including, for example, using fasteners, welding orsoldering. In some embodiments, the magnet may be at least somewhatisolated from rotation, if so desired, by placing a bearing between thepermanent magnet and the clutch shaft. Generally, magnet 90 can belocated to provide for balanced rotation by shaft 74 when the magnetrotates in unison with the clutch shaft. In this regard, magnet 90 canbe positioned to compensate for an unbalanced condition of clutch shaft74 and other components rotatably supported thereby. North and southpoles of magnet 90 are illustrated, having the north pole facingoutward. It should be appreciated that the poles of magnet 90 may bereversed, while maintaining the operational capabilities describedherein, and that it is not necessary to precisely align the magnet polesalong the axis of rotation of clutch shaft 74 for reasons which will beseen immediately hereinafter.

In the present example, an actuator magnet 92 is a permanent magnet thatis arranged having its north pole in a confronting relationship with thenorth pole of magnet 90 for use in applying a repulsive magnetic biasingforce 94 to magnet 90. For this reason, magnet 90 may be referred to asa biasing magnet. In this case, the north pole of actuator magnet 92repels the north pole of magnet 90 to provide force 94 (indicated by anarrow) on shaft 74, irrespective of any co-rotation of the biasingmagnet on shaft 74. It should be appreciated that the magnetic biasingforce can be achieved so long as one pole of the actuator magnet isrelatively closer to one of the poles of the biasing magnet. That is, ifthe north and south poles of the biasing magnetic are not aligned on theaxis of rotation of shaft 74, the actuator magnet can produce a biasingforce so long as the north and south poles of the biasing magnet projectonto the axis of rotation of clutch shaft 74 at some offset distancefrom one another Likewise, precise alignment of the poles of actuatormagnet 92 is not required. The example of FIG. 1 illustrates clutcharrangement 10 in an engaged position, corresponding to an engaged modeof the clutch arrangement, such that second gear 36 of the first gearset rotates first clutch gear 70, thereby causing second clutch gear 72to rotate first gear 32′ of the second gear set. The engaged position ismaintained by biasing force 94. It should be appreciated that, if clutchshaft 74, and thereby biasing magnet 90, move in a disengaging direction(i.e., to the left in the view of the figure), the magnitude of biasingforce 94 will increase, thereby having a positive influence onmaintaining the engaged position in the presence of external events suchas, for example, mechanical shock, gravity and the like. As will bedescribed immediately hereinafter, clutch arrangement 10 can be moved toits disengaged position by reorienting actuator magnet 92.

Turning to FIG. 2, in conjunction with FIG. 1, the former illustratesdrive train 20 with clutch arrangement 10 in its disengaged position,responsive to an attractive magnetic biasing force 96 (indicated by anarrow) that is achieved, in one manner, by reversing the poles ofactuator magnet 92 such that its south pole faces the north pole ofbiasing magnet 90. The magnetic field may be provided in a number ofways for purposes of presenting like and opposite poles to biasingmagnet 90. For example, it is noted that more than one actuator magnetmay be utilized, as will be further described below. Irrespective of thesource of the actuator magnetic field, upon reversal of the magnet polethat confronts biasing magnet 92, clutch shaft 74 moves laterally to theleft from the engaged position of FIG. 1 to the disengaged position ofFIG. 2 responsive to biasing force 96. The biasing force serves tofurther maintain the disengaged position, for example, by resistingexternal, opposing forces that may be caused by gravity and otheraccelerative influences.

Referring to FIG. 2, attention is now directed to a number of additionaldetails with respect to the illustrated embodiment. In particular, firstclutch gear 70 moves laterally to the disengaged position by an amountthat causes it to be completely clear of second gear 36 of the firstgear set. Although not required, second clutch gear 72 and first gear32′ of the second gear set can be configured to cooperate in a way whichcauses these gears to remain engaged or meshed while the overall clutchmechanism remains disengaged. This is accomplished, in the presentexample, by second clutch gear 72 having a thickness that is sufficientto allow for continuous meshed lateral sliding engagement between secondclutch gear 72 and first gear 32′, as the clutch arrangement movesbetween the engaged and the disengaged positions. Accordingly, when theclutch arrangement is moved to its engaged position, it is onlynecessary for second gear 36 and first clutch gear 70 to mesh oncontact. It should be appreciated that maintaining continuous slidingengagement between second clutch gear 72 and first gear 32′ can readilybe accomplished in a number of different ways including, for example, byconfiguring first gear 32′ with a greater thickness than second clutchgear 72, along with appropriately laterally arranging the gears relativeto one another.

Turning again to FIG. 1, as discussed above, any suitable types of gearsmay be used in clutch arrangement 10, cooperating with the remainingcomponents of drive train 20. Depending upon gear type, it should beappreciated that the clutch arrangement may be subjected to thrustforces that can tend to bias the clutch arrangement to favor either theengaged or the disengaged modes of operation. In such embodiments, themagnetic forces may, at times, necessarily be of a sufficient magnitudeto overcome the gear thrust forces. Of course, some types of gears suchas, for example, spur gears do not normally generate significant thrustforce.

Appropriate stops can be provided in order to avoid clutch arrangementgear faces from rubbing against gear faces in the overall drive train inthe engaged position of FIG. 1, as well as to avoid biasing magnet 90coming into contact with actuator magnet 92 in the disengaged positionof FIG. 2. For example, stops 82 may be provided on clutch shaft 74 inany suitable manner such as, for example, in the form of snap rings,integrally formed thrust washers and the like.

Turning now to FIGS. 3 a and 3 b, having described clutch arrangement 10in detail above, attention is now directed to one embodiment of anactuator mechanism for selectively positioning actuator magnet 92,generally indicated by the reference number 200. FIG. 3 a provides adiagrammatic elevational view of the actuator mechanism, while FIG. 3 bprovides a diagrammatic perspective view. Actuator mechanism 200includes a housing 202, which may be cylindrical, that supports actuatormagnet 92 for rotation about an axis 204, as indicated by an arrow 206,which extends through the magnetic axis of actuator magnet 92 betweenits north and south poles. It is noted that axis 204 and arrow 206 arealso shown in FIG. 1 for purposes of clarity and in one suitableorientation. Bidirectional or unidirectional rotation can be employedfor purposes of positioning magnet 92. In the present example,bidirectional rotation is used. Magnet cylinder housing 202 is rotatablysupported by a frame 208. The latter also supports a gearbox 210 havingan output that is coupled to rotate magnet cylinder housing 202 withinframe 208 and having an input (not shown) that is coupled to a motor212. In the present example, the motor is electrical, although anysuitable type of motor may be used. Accordingly, a pair of plus (+) andminus (−) motor electrical terminals 214 (FIG. 3 a) is provided forpowering the motor. Gearbox 210 can be of a reducing type such that itis not necessary for motor 212 to apply undue amounts of torque, as wellas serving to avoid undesired rotation of the magnet when the actuatormechanism is supporting the magnet in a selected biasing position. Whenactuator mechanism 200 is used as part of clutch assembly 10 of FIGS. 1and 2, frame 208 of the actuator mechanism can be mounted so as toappropriately support magnet 92 to provided for rotation 206 toselectively place the north and south poles of magnet 92 in aconfronting relationship with biasing magnet 90 (FIGS. 1 and 2). Frame208 additionally supports micro-switches 220 a and 220 b havingterminals 222 that are electrically connectable to appropriatemonitoring circuitry.

As shown in FIG. 3 a, magnet cylinder housing 202 supports switchactuator extensions 224 a and 224 b for use in actuating micro-switches220 a and 220 b, based on the position of the cylinder housing. In theexample of FIG. 3 a, a first switch actuator extension 224 a is shownengaging a plunger 228 of micro-switch 220 b, so as to indicate thatmagnet 92 is positioned with its north pole oriented as shown, forexample, in a confronting relationship with biasing magnet 90, as seenin FIG. 1. Rotation of cylinder housing 202 by 180 degrees will causesecond switch actuator extension 224 b to engage a plunger 232 ofmicro-switch 220 a, so as to indicate that magnet 92 is positioned withits south pole oriented as shown, for example, in a confrontingrelationship with biasing magnet 90, as seen in FIG. 2. Cylinder housing202 can be configured to cooperate with position detecting mechanismssuch as, for example, micro-switches in any suitable manner. Forexample, the cylinder housing can be configured with flats (i.e.,recessed areas) to produce disengagement with the micro-switches atappropriate rotational positions of the cylinder. Electrical driving andmonitoring circuitry will be discussed at an appropriate point below. Itshould be appreciated that position detection can be performed in anysuitable manner and is not limited to the use of micro-switches. Forexample, photodetector arrangements may be used in any embodiment. Oneadvantage that is associated with actuator mechanism 200 resides in thefact that it draws no electrical power once it is set to a desiredposition. Further, the mechanism will remain in the desired position ifelectrical power is lost, thereby allowing the clutch arrangement tomaintain a current operational mode, irrespective of power failure.

Turning now to FIGS. 4 a and 4 b, attention is now directed to anotherembodiment, generally indicated by the reference number 300, of anactuator mechanism for selectively exposing biasing magnet 90 of FIGS. 1and 2 to a selected polarity of magnetic field. FIG. 4 a provides adiagrammatic elevational view, in perspective, of the actuatormechanism, while FIG. 4 b provides a diagrammatic, bottom view, inperspective. Actuator mechanism 300 includes a frame 302 which supportsa magnet arm 304 (FIG. 4 a) for rotation about a pivot 306 in adirection that is indicated by an arrow 310. Magnet arm 304 may bepivotally supported in any suitable manner such as, for example, byusing a pivot shaft 312 that is received in suitable bearings 314 thatare, in turn, supported by frame 302. Magnet arm 304 supports a firstactuator magnet 320 a and a second actuator magnet 320 b. The first andsecond actuator magnets are oppositely supported by the magnet arm, asseen in FIG. 4 a, such that the north pole of magnet 320 a is visible,whereas the south pole of magnet 320 b is visible. The magnets can bemounted in the magnet arm by any suitable method including, for example,a press fit, threading engagement or through the use of suitableadhesives. Magnet arm 304 further supports a pin 322 that is positionedfor actuating paddle arms 324 a and 324 b of a pair of first and secondmicro-switches 330 a and 330 b, respectively.

Still referring to FIGS. 4 a and 4 b, motor 212 is supported by frame302, having its output shaft coupled to a gearshaft 340 for rotating aspiral gear 342. Gearshaft 340 includes a distal end 343 (FIG. 4 b) thatis supported, for example, by a suitable bearing that is received inbracket 302. Spiral gear 342 meshes with a tooth pattern 344 that isdefined, for example, by a lower end of magnet arm 304. Tooth pattern344, in one embodiment, is formed as a series of notches. In anotherembodiment, the tooth pattern can be formed as part of a separatecomponent and attached to magnet arm 304.

Application of electrical power to terminals 214(+) and 214(−) causesmotor 212 to rotate spiral gear 342 which, in turn, causes magnet arm304 to move in a direction consistent with arrow 310. In this case,polarity of electrical power that is applied to the motor terminals,determines the specific direction of rotation of magnet arm 302. In oneposition of the magnet arm, the north pole of magnet 320 a interactswith biasing magnet 90 of FIG. 1, whereas, in the other position of themagnet arm, the south pole of magnet 320 b interacts with biasing magnet90 of FIG. 1. The two positions of the magnet arm can be established onthe basis of actuation of micro-switches 330 a and 330 b, responsive tomovement of the magnet arm. That is, in one position, pin 322 actuatespaddle 324 b of switch 330 b and, in the other position (not shown), pin322 actuates paddle 324 a of switch 330 a. Generally, each micro-switch,as is the case with any embodiment described herein, can includenormally open (NO) and normally closed (NC) contacts for use by anelectrical drive arrangement, one suitable embodiment of which will bedescribed hereinafter. It should be appreciated that actuator mechanism300 shares the advantages of actuator mechanism 200, as described above.

Referring to FIG. 5, one embodiment of an electrical drive arrangement,generally indicated by the reference number 500, is illustrated that issuitable for use with the actuator mechanisms of FIGS. 3 a-b and 4 a-b.In the present example, a pair of switches 402 a and 402 b serve in themanner described above with respect to switches 220 a and 220 b of FIGS.3 a and 3 b and switches 330 a and 330 b of FIGS. 4 a and 4 b. Each ofswitches 402 a (serving as an “engaged” switch) and 402 b (serving as a“disengaged” switch) includes a common terminal. The NC1 terminals ofeach switch are normally closed when the switch is not actuated, whilethe NC2 terminals of each switch are normally open when the switch isactuated. When the actuator mechanism is at an intermediate position,switches 402 a and 402 b are in the NC1 and NC2 positions, respectively.When the actuator mechanism is in the clutch engaged position, engagedswitch 402 a is at its NO1 position, while disengaged switch 402 b is atits NC2 position. When the actuator mechanism is at its disengagedposition, engaged switch 402 a is at its NC1 position, while disengagedswitch 402 b is at its NO2 position. Power is provided, in thisembodiment, by a battery 404 which can be a storage battery thatprovides power to an overall vehicle such as, for example, an automobileor an aircraft. It should be appreciated that any suitable source ofpower can be provided. Cables 406 extend to a mode control switch 408that is a double pole double throw switch having terminals P1-P4, T1 andT2, as illustrated. The positive terminal of battery 404 is connected toP4, while the negative terminal of the battery is connected to P1 bycables 406. In one embodiment, switch 408 can be located in theinstrument panel of a vehicle, although any suitable location can beused. Terminals P2 and P3 are commonly connected to the negativeterminal of battery 404 by cables 406. In an engaged position of modecontrol switch 408, T1 is connected to the positive terminal of battery404 and T2 is connected to the negative terminal, whereas in adisengaged position of mode control switch 408, T1 is connected to thenegative terminal of battery 404 and T2 is connected to the positiveterminal. T1 is, in turn, electrically connected to NC1 of switch 402 a,while T2 is electrically connected to NC2 of switch 402 b. Commonterminal C1 of switch 402 a is electrically connected to plus terminal214(+) of motor 212, whereas common terminal C2 of switch 402 b isconnected to the minus terminal 214(−) of motor 212. Diode D1 isconnected between NC1 and NO1 of switch 402 a, as shown, while Diode D2is connected between NC2 and NO2 of switch 402 b.

Still referring to FIG. 5, when the actuator mechanism is in thedisengaged position, disengaged switch 402 b is in its NO2 positionwhile engaged switch 402 a is in its NC1 position. If mode controlswitch 408 is moved to the engaged position, current flows throughengaged switch 402 b to plus terminal 214(+) of the motor. Current flowsfrom minus terminal 214(−) to C2 of disengaged switch 402 b. Currentthen flows to NO2 of the switch and through diode D2 so as to reach T2and complete the circuit back to battery 404. At some point duringrotation of motor 212, disengaged switch 402 b changes contact from NO2to NC2; however, motor 212 will continue rotation to move the actuatormechanism toward the engaged position. Upon reaching the engagedposition, engaged switch 402 a changes contact from the NC1 terminal tothe NO1 terminal, thereby causing motor 212 to stop, with the actuatormechanism at the engaged position. When the mode control switch is nowmoved to the disengaged position, current flows from the positiveterminal of battery 404 to T2 and on to NC2 of disengaged switch 402 b.Since the switch is in the NC2 position, current flows to C2 and on tominus terminal 214(−) of motor 212. Current then flows from plusterminal 214(+) to C1 of switch 402 a, through D1 and on to the negativeterminal of battery 404 via T1 and P2 of mode control switch 408.Consequently, motor 214 rotates the mechanism toward its disengagedposition. At some point during this movement, engaged switch 402 atransits from the NO1 contact to the NC1 contact, however, movementtoward the disengaged position then continues. Again, it is noted thatthis latter condition corresponds to starting to move to the engagedposition from some intermediate position of the actuator mechanism. Uponreaching the disengaged position, disengaged switch 402 b transits fromthe NC2 contact to the NO2 contact, thereby causing motor 212 to stop atthe disengaged position. D1 and D2 allow flow of current created by theback electromotive force from the motor, causing a braking action on therotation.

FIG. 5 further illustrates a monitoring section 440 (shown within adashed line) which can provide a number of useful indications, althoughthe monitoring section is not required. Monitoring section 440 includesan exclusive nor (XNOR) gate 442 that provides a broken wire or brokenpower connection indication 444. Operation uses the connection of lines446 a and 446 b to NC1 of engaged switch 402 a and to NC2 of disengagedswitch 402 b, respectively. During normal operation, the voltages on NC1and NC2 should be opposite with respect to one another. Accordingly, thebroken wire test indicates any error condition whereby the voltages areessentially the same. Circuitry that interfaces from NC1 and NC2includes Schottky diodes S1-S4 which clamp lines 446 a and 446 b withrespect to V+ power and power returns that are indicated by triangles448. Such clamping is useful in the presence of an inductivelycharacterized component, such as motor 212, in order to lessen theopportunity for transient voltage spikes to damage the XNOR gate or anyother sensitive electronics. A resistor R1 serves to pull lines 446 aand 446 b to the same voltage value in the event of one or more openline circuit defects that can occur between battery 404, NC1 and NC2.The disconnect can occur in either the positive current leg, thenegative current leg or both. Resistors R2 and R4 serve as one logiclevel voltage divider which provides one logic level input to XNOR 442.Resistors R3 and R5 serve as another logic level voltage divider whichprovides another logic level input to the other input of XNOR 442.Again, in this exemplary embodiment, output 444 of the XNOR gate isequivalent to a true logic state, whenever the inputs to the XNOR gateare matched.

An exclusive or (XOR) gate 460 provides a motor running test 462 that isindicative of power being provided to the power terminals of motor 212.Lines 464 a and 464 b are connected to plus terminal 214(+) and minusterminal 214(−) of the motor, respectively. Schottky diodes S5-S8 serveto clamp lines 446 a and 446 b with respect to power returns that areindicated by triangles 448. Again, protection is provided by these zenerdiodes to XOR gate 460, or other sensitive electronics, from inductivetransient voltages. Resistor R10 cooperates with resistor R13 as avoltage divider to provide a logic level voltage value to one input ofXOR 460 from line 464 b, while resistor R12 cooperates with resister R14to provide a logic level voltage value to the other input of XOR 460from line 464 a. An output indication is provided by XOR 460 wheneverthe voltages at the motor terminals are opposite with respect to oneanother, as is the case when the motor is operating. An Engaging line470 exhibits a pulse 472 as motor 212 drives from a disengaged orintermediate position of the actuator mechanism to the engaged position.A negative going edge 474 of pulse 472 is indicative of the actuatormechanism having reached the engaged position. Accordingly, the negativegoing edge of pulse 472 can be latched in a known manner to provide an“engaged” indication. Similarly, a Disengaging line 480 exhibits a pulse482 as motor 212 drives from an engaged or intermediate position of theactuator mechanism to the disengaged position. Accordingly, a negativegoing edge 484 of pulse 482 can be latched in a known manner to providea “disengaged” indication.

Attention is now directed to FIG. 6 which illustrates another embodimentof a clutch arrangement, produced in accordance with the presentinvention, generally indicated by the reference number 500 and formingpart of drive train 20′. It is noted that clutch arrangement 20′ ismodified in several respects, as compared to clutch arrangement 20 ofFIGS. 1 and 2. The rotating components of the clutch assembly, however,can be essentially unchanged, as well as the interaction of the clutchassembly with second gear set 60. Hence, descriptions of these likecomponents and their operation have not been repeated for purposes ofbrevity. One difference, however, resides in the elimination of firstgear set 30 such that motor shaft gear 34 directly engages first clutchgear 70 in the engaged mode of operation that is illustrated by thepresent figure. In the disengaged mode of operation, first clutch gear70 moves to the left, as is understood in view of FIG. 2, such thatmotor shaft gear 34 is free of first clutch gear 70. It should beappreciated that first gear set 30 or any other suitable arrangement maybe interposed between the first clutch gear and the motor shaft gear, asneeded, and the present figure, as is the case with respect to all ofthe figures, is intended as descriptive rather than limiting.

Still referring to FIG. 6, modified clutch assembly 20′ is provided withan electromagnetic mode selection arrangement having a coil 510 and acontroller 520 which provides a coil current that is indicated as +/−I.Controller 520 may be made up of any suitable components and may be assimple as a battery and a switch in a series connection. The switch canbe mechanical or electronic. When +I is flowing in coil 510, the coilproduces a magnetic field 522 (only a few flux lines of which have beenshown) to urge biasing magnet 90, for example, to the right in the viewof the figure, to move clutch arrangement 20′ to its engaged positionand, thereafter, to maintain the engaged position. On the other hand,when −I is caused to flow in coil 510, the coil produces magnetic field522 with an opposite polarity to attract biasing magnet 90 so as to movethe clutch assembly to the left, in the view of FIG. 5, to itsdisengaged position. Continued application of current can be used tocontinuously bias the clutch assembly to its disengaged position so asto resist forces such as, for example, external accelerations. Ofcourse, the engaged position can be similarly maintained through thecontinuous application of current. In some embodiments, there may be noneed to continuously apply coil current, once a desired position of theclutch arrangement has been achieved. In other embodiments, gear typesmay be selected that produce a thrust force which can either tend tomove the clutch arrangement into the disengaged position or the engagedposition. Application of current I can then be established, based on theintroduced thrust forces. In this regard, the magnitude of +I can bedifferent than the magnitude of −I. For example, if +I biases the clutchassembly toward the engaged position, and the gears cooperate to providea thrust force that also biases the gears to an engaged position, arelatively lower magnitude of current +I can be employed once theengaged position has been achieved. On the other hand, if the thrustforce tends to cause disengagement of the clutch arrangement, arelatively higher magnitude of current +I can be used. It should also beappreciated that locking mechanisms can be employed to maintain theengaged and disengaged positions of clutch shaft 74. For example, alatch coil and latch arm can be provided adjacent to the clutch shaftsuch that lateral movement out of the engaged or disengaged positions isprevented unless the latch coil and latch are operated to disengage withclutch shaft 74. In one embodiment, the latch coil simultaneouslyreceives drive current with clutch coil 510. In a more detailedembodiment, the latch coil and clutch coil can be electrically connectedin series.

In view of the foregoing, it can be seen that a clutch shaft, having apair of opposing ends, supports the clutch gear such as, for example,clutch gear 70 of FIGS. 1 and 2, for rotation about an axis of rotation.The clutch shaft is further supported for lateral movement along theaxis of rotation such that the clutch gear is inserted into the drivetrain at a first lateral position in a first operational mode to causethe output shaft to turn responsive to rotation of the input shaft andremoved from the drive train at a second lateral position in a secondoperational mode to disengage the output shaft from rotation of theinput shaft. As will be seen, however, the concepts that have beenbrought to light herein are not limited to clutch arrangements.

Attention is now directed to FIGS. 7 and 8 which illustrate oneembodiment of a transmission arrangement, generally indicated by thereference number 600 and forming part of a drive train 602. It is notedthat components such as, for example, bearings and stops have not beenshown for purposes of illustrative clarity, but are understood to bepresent and are considered to be readily provided by one having ordinaryskill in the art. A number of components are shared with aforedescribedclutch arrangement 10 and drive train 20. Accordingly, these sharedcomponents are designated by like reference numbers and theirdescriptions have not been repeated for purposes of brevity. In thepresent example, the first gear set further includes a third gear 604that is located on first gear set shaft 38 in a spaced apartrelationship from second gear 36. A traveling gear shaft 74′, previouslydesignated as clutch gear shaft 74 with reference to FIGS. 1 and 2,supports a first transmission gear 70′ and a second transmission gear72′, which were previously referred to as first clutch gear 70 andsecond clutch gear 72. Traveling shaft 74′ additionally supports a thirdtransmission gear 606.

Drive train 602 is operable in the mode shown with respect to FIG. 7,which corresponds to the engaged mode of the clutch arrangement of FIG.1, so as to provide a first gear ratio between the input, motor shaft ofmotor 22 and second, output gear set shaft 38′.

Referring to FIG. 8, when traveling gear shaft 74′ is caused to move tothe left in the view of the figure, using magnetic attraction, thirdgear 604 of the first gear set shaft engages third transmission gear606. This engagement takes place after second gear 36 of the first gearset disengages from first transmission gear 70′. Once engagement betweenthird gear 604 and third transmission gear 606 takes place, a secondgear ratio is provided between the input, motor shaft and second, outputgear set shaft 38′. Accordingly, selectable gear ratios have beenprovided. Any suitable arrangement can be used for purposes of moving,biasing and maintaining the position of traveling shaft 74′, via magnet90, including those described above. Of course, removal of third gear604 and third transmission gear 606 results in a clutch type arrangementwith operation consistent with that of FIGS. 1 and 2. It should beappreciated that any suitable form of actuator may be employed forpurposes of biasing magnet 90 including those described above. Further,the aforedescribed transmission arrangement, as well as a reversingconfiguration, yet to be described, shares the advantages of the clutcharrangement described above, for example, with respect to maintaining anoperational mode despite power loss and provides for embodiments thatmaintain an operational mode with no or little electrical powerconsumption.

Turning now to FIGS. 9 and 10, one embodiment of a reversibletransmission arrangement is illustrated, generally indicated by thereference number 700 and forming part of a drive train 702. A number ofcomponents are shared with aforedescribed transmission arrangement 600and drive train 602. Accordingly, these shared components are designatedby like reference numbers and their descriptions have not been repeatedfor purposes of brevity. In the present example, second transmissiongear 72′ (FIGS. 7 and 8) has been replaced with a modified transmissiongear 704, for reasons which will become evident. Further, a reversingidler arrangement 710 includes a reverse idler shaft 712 that supports afirst reverse idler gear 714 and a second reverse idler gear 716. Outputshaft 38′ additionally supports a reverse gear 718 that continuouslymeshes with second reverse idler gear 716.

Referring to FIG. 9, in providing a first gear ratio between the input,motor shaft of motor 22 and output shaft 38′, the drive train operatesin essentially the same manner as drive train 602 and transmission 600of FIG. 7, with the exception of the rotation of the components ofreversing idler arrangement 710.

Referring to FIG. 10, in providing a second gear ratio, however, byusing magnet 90 to move traveling shaft 74′ to its leftmost position, inthe view of the figure, modified transmission gear 704 and first gear32′ of second gear set 60 initially disengage. Thereafter, thirdtransmission gear 606 engages first reverse idler gear 714 which causesreverse gear 718 to rotate output shaft 38′ in a reversed direction, asindicated by arrow 52 and in comparison with FIG. 9. It should beappreciated that the first and second gear ratios can be set relative toone another, as desired, with appropriate selection of gears or thefirst and second gear ratios can be equal, resulting only in reversal ofrotation.

Attention is now directed to FIGS. 11 and 12 which illustrate oneembodiment of a friction clutch arrangement, generally indicated by thereference number 800 and forming part of a drive train 802. A number ofcomponents are shared with aforedescribed embodiments and are designatedby like reference numbers. In the present example, shaft gear 34 ofmotor 22, rotating in direction 50, drives a clutch gear 804 that issupported, for example, by a bushing 810 such that the bushing andclutch gear 804 can co-rotate freely about an axis of rotation 814 onclutch shaft 74 responsive to rotation of shaft gear 34. At the sametime, clutch shaft 74 is free to move laterally within bushing 810 alongaxis 814. Bushing 810, in one embodiment, may be pressed into clutchgear 804, although any suitable form of attachment may be used. Bushing810 is further supported by a bearing 812, which is diagrammaticallyshown, to allow for free rotation of the bushing and, therefore, clutchgear 804 while fixing the lateral position of the bushing and clutchgear along axis 814. Bearing 812 may be of any suitable type, as will beappreciated by one having ordinary skill in the art in view of thisdisclosure. Clutch gear 804 further defines a clutch face 816. A clutchplate 820 is fixedly attached to clutch shaft 74 to rotate in unisontherewith and for lateral movement with the clutch shaft. Clutch plate820 includes a friction surface 822 that is in a confrontingrelationship with clutch face 816 of the clutch gear. The clutch platemay be integrally formed or may be formed having various functionallayers (not shown). For example, a rigid backing plate may support asuitable friction material, as will be familiar to one having ordinaryskill in the art. In another embodiment, clutch gear 804 may support afriction material (not shown) that is engaged by the clutch plate or afriction material that is supported by the clutch plate. Stops 82 a and82 b are arranged on opposing sides of bearing 76, and may be configuredas described above. Biasing magnet 90 is supported on shaft 74 asdescribed above with respect to FIG. 1. Actuator magnet 92 is likewiseused in the manner that is described above with respect to FIG. 1.Further, the actuator embodiment of FIGS. 4 a and 4 b may replaceactuator magnet 92. In another embodiment, the actuator magnet can bereplace by an electromagnet, for example, in the manner that isillustrated in FIG. 6.

Still referring to FIGS. 11 and 12, a clutch shaft gear 830 is fixedlysupported on clutch shaft 74 to rotate in unison with the shaft and tomove laterally therewith. The clutch shaft gear is in engagement with anoutput gear 832 that is fixedly supported on an output shaft 834 thatcan be used to drive any suitable mechanism either directly or throughanother gear that is positioned on shaft 834. Output shaft 834 issupported by bearings 40 which can be of any suitable type that allowsfree rotation of the shaft and capture the shaft with respect tolimiting lateral movement. Although not required, output gear 832 andclutch shaft gear 830 can be configured to cooperate in a way whichcauses these gears to remain engaged or meshed while the clutchmechanism is in the disengaged position of FIG. 11 to allow forcontinuous meshed lateral sliding engagement between the clutch shaftgear and the output gear. In the present example, output gear 832 has athickness that is greater than the thickness of clutch shaft gear 830,although this is not a requirement.

Referring to FIG. 11, clutch arrangement 800 is illustrated in adisengaged position in which clutch plate 820 is spaced away from clutchgear 804 as a result of an attractive biasing force 836, indicated usingan arrow, that is applied as a result of attraction between biasingmagnet 90 and actuator magnet 92. It should be appreciated that thedisengaged position of FIG. 11 need only place friction surface 822 ofthe clutch plate a small distance away from clutch face 816 of theclutch gear sufficient to avoid contact between the opposing surfaces.With the clutch plate in the disengaged position, clutch gear 804 andbushing 810 rotate on clutch shaft 74. It should be appreciated that theuse of bushing 810 is considered to be suitable since a no loadcondition is present with the clutch plate in the disengaged position.In some embodiments, bushing 810 can be replaced by a bearing, forexample, if a significant load is experienced when the clutch isdisengaged. Lateral travel of the clutch shaft is limited, in thisexample, by stop 82 a in order to avoid contact between biasing magnet90 and actuator magnet 92.

Referring to FIG. 12, clutch arrangement 800 is illustrated in anengaged position in which friction surface 822 of clutch plate 820 isbiased into contact with clutch face 816 of the clutch gear as a resultof a repulsive biasing force 838, indicated by an arrow. In the engagedposition, clutch plate 820 co-rotates with clutch gear 804 which, inturn, rotate clutch shaft 74 along with clutch shaft gear 830.Accordingly, the clutch shaft gear rotates output gear 832. It should beappreciated that bushing 810 rotates with clutch gear 804 and clutchshaft 74 when the clutch plate is in the engaged position such thatbushing 810 experiences minor loading and no relative rotation withrespect to clutch shaft 74. As is the case with any friction clutch, thefrictional characteristics between friction surface 822 of the clutchplate and clutch face 816 of the clutch gear should be considered aswell as anticipated loads in order to establish an appropriate value forbiasing force 838. Although stop 82 b has been illustrated which limitslateral motion of the clutch plate toward the clutch gear, stop 82 b maybe optional. This stop may be useful, for example, in avoiding undesiredcontact with an underlying material as a result of progressive wear ofan overlying layer of friction material.

While a number of exemplary aspects and embodiments have been discussedabove, those of skill in the art will recognize certain modifications,permutations, additions and sub-combinations thereof. For example, theclutch, reversing and gear shift arrangements described herein can beused as functional blocks in a series where the output shaft of onearrangement serves as the input shaft of the next. Accordingly, thedrive arrangements that have been disclosed herein enjoy a wide range ofpractical applications including, but not limited to transmissions forvehicles, auto-pilots including those for airplanes and helicopters, aswell as in robotics applications. It should be appreciated that theforegoing embodiments are not limited to implementation with gears solong as the advantageous actuation concepts that have been brought tolight herein are being applied. For example, some embodiments mayreplace gears with rollers having frictionally engagable surfaces suchas, for example, resilient, rubber-like rollers or some combination ofresilient and solid rollers. It is therefore intended that the followingappended claims and claims hereafter introduced are interpreted toinclude all such modifications, permutations, additions andsub-combinations as are within their true spirit and scope.

What is claimed is:
 1. An apparatus for use in a drive train at leastincluding an input shaft and an output shaft, said apparatus comprising:a gear configured to rotate about an axis of rotation; a traveling shaftsupporting said gear for rotation about said axis of rotation and havinga pair of opposing ends and said traveling shaft further supported forlateral movement along said axis of rotation such that the gear servesas a traveling gear that cooperates with the drive train at a firstlateral position in a first operational mode to cause the output shaftto respond in a first way responsive to rotation of the input shaft andto cooperate with the drive train at a second lateral position in asecond operational mode to cause the output shaft to respond in a secondway responsive to rotation of the input shaft wherein one end of theopposing ends of the traveling shaft is a free end; and a permanentmagnet that is fixedly mounted on the free end of said traveling shaftfor movement with the traveling shaft and arranged for applying amagnetic biasing force along the axis of rotation to move the travelinggear arrangement between the first lateral position and the secondlateral position responsive to an external magnetic field.
 2. Theapparatus of claim 1 wherein said permanent magnet includes opposingnorth and south poles and said traveling shaft supports the permanentmagnet with one of the north and south poles facing outward with respectto the free end of the traveling shaft and the other one of the northand south poles confronting the free end of the traveling shaft.
 3. Theapparatus of claim 2 wherein said permanent magnet is positioned tocompensate for an unbalanced condition of the traveling shaft to providefor balanced rotation of the traveling shaft.
 4. The apparatus of claim1 further comprising: an actuator that is configured for producing theexternal magnetic field to cause said permanent magnet to move saidtraveling shaft and, thereby, said gear away from the second lateralposition to continuously magnetically bias the clutch member into saidfirst lateral position, and for producing the external magnetic field inan opposite orientation to cause the permanent magnet to move the gearaway from the first lateral position to continuously magnetically biasthe gear into said second lateral position.
 5. The apparatus of claim 1wherein said permanent magnet includes a north pole and a south polethat are arranged such that a projection of the north and south polesonto said axis of rotation results in an offset along said axis betweenprojected north and south pole positions.
 6. The apparatus of claim 1wherein the first operational mode causes the output shaft to rotateresponsive to rotation of the input shaft and the second operationalmode disengages the output shaft from rotation responsive to rotation ofthe input shaft.